The present invention relates to electronic systems and methods for accurately locating stationary or moving objects, and more particularly, to a system and method that utilizes high frequency sound waves to precisely locate and track multiple personnel within confined areas such as buildings.
There are many instances where law enforcement personnel or soldiers need to carry out well coordinated operations in urban terrain. For example, team members of special weapons and tactics (SWAT) units need to follow very special coordinated movements when raiding a building where hostages are being held. As another example, team members of military commando units must adhere to strict rules of advancement and engagement when clearing a building suspected of housing snipers. It is therefore necessary for such law enforcement personnel and soldiers to receive rigorous training in environments that simulate real-life expected conditions as closely as possible. It is desirable that the instructors have a highly accurate real time picture of the precise location and movement of each member of the assault team. Optimally the instructors need to know the identity of each soldier and his or her precise movements from room-to-room.
It is difficult to track the movements of military commandos during simulated urban assaults because they often take place in complete darkness thus requiring the use of infrared night vision devices. Therefore, it is not possible simply to use video surveillance. Infrared tracking is not a viable option because the rooms are often smoke filled. Infrared tracking also requires mirrors and other delicate devices not well suited for harsh training environments. Furthermore, infrared tracking could interfere with MILES training equipment often used by the U.S. Army. A radar-based locating system would not be appropriate for simulated urban training environments because of the distortions induced by the building structures such as steel door frames that would impair location accuracy. In any case, radar cannot give very precise distance measurements where the distances being measured are relatively small. A GPS-based locating system would not be practical for simulated urban training environments because location accuracy would be insufficient, even assuming that enough satellite signal strength could be acquired inside of the building without distortion from steel columns and rebar.
In addition to locating and tracking multiple personnel within a building, it would also be desirable in addition to be able to determine both the azimuth and elevation of such personnel to determine, for example, the direction that each soldier is facing and whether each soldier is standing, lying, climbing, descending or perched off the floor. It would further be desirable to provide an indication of the direction that each solder is pointing his or her weapon.